(a) Technical Field of the Invention
The present invention generally relates to the pistol nozzle of a hose, and more particularly to a pistol nozzle utilizing a spherical valve to control the water flow.
(b) Description of the Prior Art
FIGS. 4 and 5 depict the structure and operation of a conventional pistol nozzle. As illustrated, inside the body 20 of the pistol nozzle, there is a water channel 21 whose intermediate section has a valve 24 permitting or blocking the water to flow through the water channel 21. The valve 24 is an integral part of a shaft 23 whose one end is in direct contact with a control lever 22 of the pistol nozzle, and whose the other end is wound in a helix spring 25. When a user grasps the control lever 22, the control lever 22 pushes the shaft 23 which in turn compresses the helix spring 25 and opens the valve 24 to allow the water to flow through the water channel 21. When the control lever 22 is released, the helix spring 25 restores the shaft 23 and, thereby, the valve 24 to their normally closed locations, which shuts down the water flow.
The valve 24 usually has a sharp contact with the cross-section of the water channel 21, and the contact would soon wear down after a period of usage and under the impact of high-pressured water flow. Also a plug-like shape of the valve 24 helps to accumulate debris and develop incrustation on the valve 24. As a result, water leakage through the valve 24 is not uncommon as the valve 24 cannot provide an air-tight blockade to the water flow. The leakage is a waste of water and is often rather annoying to the user. This leakage problem would trouble the user even more when the pistol nozzle is used to spray a liquid chemical which may be erosive or poisonous.